NanosafetyNanotechnology is expanding at a breathtaking pace and every day witnesses the development of materials or technologies that improve our knowledge and capacities. Novel nanomaterials are also leaving the laboratory to arrive the consumer in the form of new products and devices that include different kind of engineered nanoparticles (ENPs).
Nanotechnology is expanding at a breathtaking pace and every day witnesses the development of materials or technologies that improve our knowledge and capacities. Novel nanomaterials are also leaving the laboratory to arrive the consumer in the form of new products and devices that include different kind of engineered nanoparticles (ENPs).
These novel applications have triggered the concerns on the possible harmful impact of ENPs in both the human health and the environment. The risks associated to inhalation, skin absorption and ingestion of nanoparticles are being currently addressed by studies involving cell toxicity or in vivo investigations with laboratory animals. However, a comparatively smaller effort has been directed to the development of engineering approaches to tackle these risks reducing human exposure and designing new handling procedures for ENPs to ultimately eliminate the associated hazards.
Here the group research is focused on engineering approaches to increase nanomaterials-related safety. Current subjects under study include nanoparticle sampling in the workplace or the environment, labelling of nanomaterials to allow identification, monitoring the emission of nanomaterials in different scenarios and the establishment of safety procedures in the processing of nanomaterials. In our group we are committed to develop engineering processes for identifying nanotechnological risks and challenging Nanosafety from five different approaches:
- Generation of nanoparticle aerosols. Focusing on the formation of nanoparticle-laden aerosol streams in working atmospheres, we are developing novel aerosol sources that mimic the natural aerosol formation in working atmospheres. In our group we are currently developing techniques for nanoparticle aerosol generation from liquid dispersions and solid powders. Our aim is to produce stable nanoparticle aerosol currents with tunable concentrations and particle sizes.
To this end, we have designed aerosol generators based in liquid suspensions of nanoparticles able to produce nanoparticle streams up to 107 particles/mL for periods longer than 24 h. Also, fluidized bed aerosol generators (FBAG) are being set up for producing nanoparticle streams from solid sources.
- Aerosol dynamics of nanoparticles in exposure chambers. We have built specifically designed laboratory spaces that allow us to monitor the aerosol evolution. These dispersion chambers are a lineal aggregation tube for analyzing the kinetics of nanoparticle agglomeration and collapse in different airflows and a large glove-box assembly where the behavior of nanoparticle aerosols is analyzed in a controlled environment that mimic the laboratory conditions. Also, we are operating a large-scale room with controlled atmosphere conditions for determining nanoparticle distribution and evolution in different locations. This setup also has a self-cleaning device that allows a rapid re-conditioning after the nanoparticle dispersion experiments. The strength of this installation relies in the ability of determine the aerosol formation and evolution without the influence of external environmental nanoparticles, which allows a closer approach to the real laboratory conditions in nanotechnology
Self-cleaning testing aerosol dispersion room for exposure assessment of nanomaterials
For the determination of particle concentration in aerosols with sizes between 300 nm and 20 µm an 8-channel optical particle counter (OPC, Model #1.108; Grimm Aerosol Technik) is used. The fraction of smaller aerosol particles (between 10 and 1100 nm) was determined using a scanning mobility particle spectrometer (SMPS, Model #5.403; Grimm Aerosol Technik) that comprises a differential mobility analyzer (DMA) and a condensation particle counter (CPC). The inlet aerosol in the SMPS system is electrically neutralized using a 241Am alpha-emission source to provide an equalized distribution of charges on the surface of nanoparticles. Moreover, a particle measurement system NPS500 with a corona charger was used. This equipment provides the ability to measure particle size distributions over a range of 5 nm to 500 nm. Gravimetric analysis of the deposited aerosol nanoparticles is performed using arrays of quartz crystal microbalances (QCM) at specific locations around the aerosol source. Offline study of nanoparticles is carried out collecting nanoparticles from the aerosol streams on TEM grids and SEM tapes for morphology determination and on polymer filter units for chemical analysis using X-ray photoelectron spectroscopy (XPS) and X-ray fluorescence (XRF).
- Labeling nanoparticles for risk identification. A key aspect in nanosafety is the identification of ENPs in the atmosphere. As our environment is already teeming with nanoparticles, some (e.g. SiO2) resulting from natural erosion processes, and some (e.g. carbon from combustion engines) man-made, the adequate tagging of ENPs is essential to be able to follow their fate in several media. In our group, methods for efficient identification of nanoparticles in different environments are currently under research. Our approach is based in introducing trace amounts of lanthanide oxides in both SiO2 and TiO2 nanoparticles, taking advantage of the relatively low concentration of rare earths in the environment. Tagged nanoparticles show similar size and surface characteristics than label-free particles, with label concentrations up to 10% (w/w). Identification is carried out using XPS and XRF analysis, together with TEM and SEM imaging. Up to date, less than 10% of labeled nanoparticles can be effectively identified among non-labeled counterparts of the same size.
Optical labeling of nanoparticles is also investigated for enhancing sensitivity of identification. We are investigating on flurorophor markers such as fluorescein isothiocyanate (FITC), [Ru(phen)3]2+, rhodamine B (RhB),… that are grafted to SiO2 and TiO2 nanoparticles. On the other hand, luminescent oxide nanoparticles such as Er2O3 and Eu2O3 are trapped in core-shell SiO2 nanostructures. In both cases, the identification is performed using UV/vis spectrometry and fluorescence spectroscopy (FS) at different excitation wavelengths depending on the composition and structure of nanoparticles. We have developed several methods for optical labelling of nanoparticles enhancing sensitivity of its identification. It has allowed identifying the emitted nanoparticles in the environment (e.g. real water streams) down to trace concentration levels (under 10 ng/mL) in both liquid and air media. The adequate tagging of ENPs is crucial to open new challenges and opportunities in assessment, monitoring and imaging of those nanomaterials for safety and toxicological studies.
- Design of systems for capturing nanoparticle aerosols. Another area of interest relates to the treatment of liquid and gas streams containing nanoparticles, for which there are no well-established protocols. We are investigating different sequestration methods (nanofiltration, liquid jet capture) to obtain a residue that can be disposed of by conventional methods.
- We also focus on developing adequate procedures for safe handling and monitoring of a variety of nanomaterials of current use in technological and biomedical applications. The exposure of laboratory workers to nanoparticles is specifically investigated, as well as the assessment of the efficiency of some protective measures (laminar flow hoods, masks). These devices are commonly used, in spite of the fact that they most have not been designed to protect from nanoparticles.
MAIN COLLABORATIONS:• Rudolf Reuther. Nordmiljö AB, Sweden
• Albert Duschl. Paris-Lodron-University Salzburg, Austria
• Manuel Alonso. Centro Nacional de Investigaciones Metalúrgicas (CENIM-CSIC), Madrid, Spain
• Julià Sempere. Institut Quimic de Sarrià (IQS), Barcelona, Spain
• Celina Vaquero. Centro Tecnológico LEIA, Miñano (Álava), Spain
SOME RECENT RELATED PUBLICATIONS:
- "Fluidized bed generation of stable silica nanoparticle aerosols”, Clemente, A., Balas, F., Lobera, M. P., Irusta, S., & Santamaria, J. Aerosol Science and Technology, 47(8), 867-874 (2013). doi: 10.1080/02786826.2013.797952
- "Intense generation of respirable metal nanoparticles from a low-power soldering unit”, Gómez, V., Irusta, S., Balas, F., & Santamaria, J. Journal of Hazardous Materials, 256-257, 84-89 (2013). doi: 10.1016/j.jhazmat.2013.03.067
- "Generation of TiO2 aerosols from liquid suspensions: Influence of colloid characteristics” V. Gómez, S. Irusta, F. Balas,J Santamaria.. Aer. Sci. Techol.,DOI:10.1080/02786826.2013.845645, (2013)
- “Microwave-assisted mild-temperature preparation of neodymium-doped titania for the improved photodegradation of water contaminants”, Gomez, Virginia, Balu, Alina Mariana, Serrano-Ruiz, Juan Carlos, Irusta, Silvia, Dionysiou, Dionysios D., Luque, Rafael, Santamaría, Jesús. Applied Catalysis A: General. 441–442(0), 47-53 (2012).
- “Reported Nanosafety Practices in Research Laboratories Worldwide”, Balas, F. et al. Nature Nanotechnology. 5(2), 93-96 (2010).
- “Nanomaterial release from nanocomposites during reworking process”. Gómez, V., Levin, M., Irusta, S., Dal Maso, M., Santamaría, J., Jensen, K.A., and Koponen, I.K. International Conference on Safe production and use of nanomaterials, Nanosafe, Grenoble, Francia (2012)
- “Aerosol emission assessment during soldering process”, Gómez, V., Irusta, S., Balas, F., and Santamaría, J. International Conference on Safe production and use of nanomaterials, Nanosafe, Grenoble, Francia (2012).
- “Nanopartículas de óxido de titanio dopadas con neodimio aplicadas a la degradación fotocatalítica de contaminantes en agua”, Gómez, V., Irusta, S., Balas, F., and Santamaría, J. Congreso Iberoamericano de Catálisis (CICAT), Santa Fe, Argentina (2012)
- “Síntesis, caracterización y estudio fotocatalítico de nanopartículas de óxido de titanio dopadas con neodimio”, Gómez, V., Irusta, S., Balas, F., and Santamaría, J. Sociedad Española de Catálisis (SECAT). Zaragoza, Spain (2012).
- “Rare earth labelling of TiO2 engineered nanoparticles for identification of aerosols in occupational environments”, Gomez, V. et al. European Aerosol Conference (EAC2011), Manchester 2011
- “Effect of Image Force on Penetration of Nanoparticles through a Laminar Flow Tube”, Gomez, V. et al. European Aerosol Conference (EAC2011), Manchester 2011
- “Rare Earth Labeling of TiO2 Nanoparticles for Aerosol Quantification and Identification in Occupational Hygiene Studies”, Gomez, V. et al. 5th International Conference on Nanotechnology and Occupational Health (NanOEH2011), Boston 2011
- “One-step microwave synthesis and characterization of gadolinium-doped titania nanoparticles”, Gómez, V., Irusta, S., Balas, F., and Santamaría, J. Trends in Nanotechnology (TNT10), Braga, Portugal (2010).
- “NANOSOST: The Spanish Initiative for a Safe and Sustainable Nanotechnology”, Santamaría, J. et al. 4th International Conference on Nanotechnology and Occupational Health (NanOEH2009), Helsinki 2009.
PUBLIC FUNDED PROJECTS:
- NanoValid (http://www.nanovalid.eu/) EU-FP7-26314
- NanoTrap, Desarrollo de Técnicas de Monitorización y Captura de Nanopartículas. MAT2008-01319/NAN
- NANOSOST. Hacia una nanotecnología responsable, segura y sostenible (Proyecto cofinanciado por: FEDER PSE-420000-2008-003)
- Sub-proyecto 1. Caracterización, Metrología y Generación de Referencias PSS-420000-2008-11
- Sub-proyecto 4. Bases Científicas para la Medición del Riesgo PSS-420000-2008-14
- Sub-proyecto 5. Bases Científicas para el Control del Riesgo PSS-420000-2008-15
- Sub-proyecto 6. Materiales para Aplicaciones Barrera PSS-420000-2008-15